I suppose you can consider this as the "follow-up" to my original essay on why Quantum Mechanics is so difficult . ~ Achilles 08:13, 23 Mar 2005 (UTC). (Note there is no “symmetry” to be broken; in one case the cat evolved by stopping at the scratching post, and in the other by stopping at the food bowl, so the two cases are different.). When I wrote From Eternity to Here, I fooled everybody with an unprecedented step: I put my intro to QM late in the book, in Chapter 11. In quantum mechanics, we can't solve the one-body problem, and with quantum electro dynamics, we don't even understand the vacuum anymore. It displaces the ground back and forth by some distance, even away from the AB line. The first principle is that you must not fool yourself, and you are the easiest person to fool. Anybody here know a source for this quote/story? Thanks, Sam nead 19:10, 9 September 2006 (UTC), Feynman was a truly great teacher. On a completely separate note, regarding the low entropy state of the early universe: might negative temperatures provide a clue? And Conway too says that he didn’t understand the quantum physics lectures … Seems a paraphrase of the exchange (quoted above and on the main page) on teaching why spin-1/2 particles follow Fermi-Diract statistics. *sadface*. ), "First you guess. If anyone is curious about quantum field theory, I strongly recommend the book, “Fields of Color: The theory that escaped Einstein” by Rodney Brooks. In that case, the final wave function assigns a negative amplitude to the table, and a positive one to the sofa…, As I try to chase down the mystery, it keeps finding new places to hide. which field they belong to), where and when they are and their state of motion, are merely ways of describing states of fields.Firstly, fields are more fundamental. It depends on which energy acting on the subatomic particles was stronger. But some researchers say they have ... To understand the role of quantum mechanics in ... is what will ultimately help us understand how we can control the quantum world. To come back to the question of this post, we have several answers which are consistent : if some people say that they do not understand quantum mechanics, this is either because they … I can diagonalize Hamiltonians just fine, but I don’t think I really grok what Employing conventional quantum mechanics, they obtained some … -- Sburke 15:19, 22 February 2011 (UTC), I am familiar with this quote, but I'm not sure this is the form I originally heard it in: But he came back a few days later to say, "I couldn't do it. The quote, exact words, "If you think you understand quantum mechanics, you don't understand quantum mechanics." Of course, physicists famously don’t quite agree about what quantum mechanics actually says. I … Julia explains what she learned about quantum mechanics (and in particular the Many Worlds interpretation) from a chat with physicist Sean Carroll. Because, to paraphrase a recent "Incredible" cartoon: to say everything is special is to say NOTHING is. Remarks after bongo drum session at Caltech (13 Jul 1953), "If you're not having fun, you're not learning. He says it in a university lecture called The Character of Physical Law - (Anon 2014). Or is it a misattribution? What Feynman actually said is on the quotes page under "Character of Physical Law". In quantum mechanics, the location of the electron orbiting an atom is described by its wave function, which gives only a probability of where you might find it. Do you know of any similarly clear account at a higher mathematical level? He says he himself does not really understand … Why do we quote Feynman, and not his mother, or his next door neighbor? They also have a Feynman-quote in that article, "I think I can safely say that nobody understands quantum mechanics." A photon is not a probability. (He’d like to mention to this comment spread he’s very much alive and needs boosters.) Sean, thank you very much for writing this, and for making it freely available initial?) If a scientist is correctly applying quantum mechanics, they will use more specific (and hence more complicated) language. It is shown how to extract the odds for getting different values of momentum from a generic wave function by writing it as a sum over functions of definite momentum. The quote popularly attributed to physicist Richard Feynman is still true: if you think you understand quantum mechanics, then you don’t. … Sizing up his audience perfectly, Feynman said, "I'll prepare a freshman lecture on it." OK! This is absolutely Feynman. Also the idea that classically we can keep back reactions of measurements as small as we want but in the quantum world there is a minimum action given by h_bar. If mathematics had never been invented, physics would have been set back exactly (about?) But twenty years later, I think the reason so many people believe one cannot understand quantum mechanics is because they are constantly being told they can’t understand it. If someone does the exact opposite, then he completely misunderstands quantum mechanics, instead of understanding it! It must be those details and aspects you refer to that determine the negative. Introduction to the book is found here http://www.quantum-field-theory.net, A more complete, long, and extremely enlightening series of posts on QM insterpretation is found at the Less Wrong website. But in these experiments, there is still the issue of the random number generator used to select stimuli being entangled with the rest of the system. Sure, you can do pretty well in just five words, but sometimes you need to be a little more expansive. Prof. John Cramer, who developed the Transactional Interpretation, is building a retrocausal signalling system to test his ideas. On that note, there is already published physiological evidence from many independent experiments of physiological retrocausal information transfer at the 6.9 sigma level which definitely looks pretty convincing (I was skeptical originally so I personally replicated one such experiment [published after the time frame of the meta-analysis, so not included in the 6.9, but showing a very strong signal] with some modifications to further rule out mundane explanations. Emergence, The Biggest Ideas in the Universe | 20. They work with quantum theory, even though they don’t understand it. C included. Funny: My kitten, Shrodinger had his vet visit on August 12th. Until physicists definitively answer these questions, they can’t really be said to understand quantum mechanics — thus Feynman’s lament. This page was last edited on 25 November 2020, at 19:36. —Richard Feynman, The Character of Physical Law (MIT Press: Cambridge, Massachusetts, 1995), 129. The relevant question is, if the emergence of classicality can be understood on the basis of only quantum mechanics as it stands today (as in the case of thermodynamics from stochastic mechanics) or if there is some ingredient missing, something one would need to modify about quantum mechanics. You don't like it..., go somewhere else! Many outsiders figure that they don’t understand quantum theory because they can’t see how an object can be in two places at once, or how a particle can also be a wave. Wikiquote no longer allows unsourced quotations, and they are in process of being removed from our pages (see Wikiquote:Limits on quotations); but if you can provide a reliable and precise source for any quote on this list please move it to Richard Feynman. I think it’s much more interesting to live, not knowing, than to have answers which might be wrong.” The interview’s here: https://www.youtube.com/watch?v=I1tKEvN3DF0, Near the end of this beautiful excerpt he said it: "I can live with doubt, and uncertainty, and not knowing. : 1.1 It is the foundation of all quantum physics including quantum chemistry, quantum field theory, quantum technology, and quantum information science. I've always known quantum nonlocality has nuances, but stuff I read this week revealed some wrinkles I wasn't aware of. But really, this is tackling a different issue, and it is something that some time even physicists have mentioned, often to convey a message to the general public. 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